Myth #1: But what if my cell phone doesn’t have SMS/signal, or I’m in a foreign country?
Reality: You can install a standalone app called Google Authenticator (it’s also available in the App Store), so your cell phone doesn’t need a signal.

Myth #2: Okay, but what about if my cell phone runs out of power, or my phone is stolen?
Reality: You can print out a small piece of paper with 10 one-time rescue codes and put that in your wallet. Use those one-time codes to log in even without your phone.

Myth #3: Don’t I have to fiddle with an extra PIN every time I log in?
Reality: You can tell Google to trust your computer for 30 days and sometimes even longer.

I just turned it on for my Google account, and I am trying to figure out why I didn’t a long time ago. For those unfamiliar with how it works: When you login to your Google account on a new computer, it will ask for both your password and a verification code. The code is sent through text message when logging in or it can be shared through the Google Authenticator app. It is so simple and keeps your account safe.

Seriously if you have not, turn it on. There is no reason otherwise. [Matt Cutts]